Henry Harcourt Hyde Clarke, known as Hyde Clarke, (14 December 1815 – 1 March 1895) was an English engineer, philologist and author.

The son of Henry and Susannah Clarke, he was born at Little Bell Alley, Barbican in London. He edited the Railway Register from 1845 to 1847 and founded the London and County Bank. He was a member of the British Association for the Advancement of Science. He was expelled from the Anthropological Society of London on 22 August 1868[1] in the wake of public allegations he had made concerning (chiefly) the mismanagement of accounts of that body. He was elected a Fellow of the Royal Statistical Society on 19 December 1876.

A short handbook of the comparative philology of the English, Anglo-Saxon, Frisian, Flemish or Dutch, Low or Platt Dutch, High Dutch or German, Danish, Swedish, Icelandic, Latin, Italian, French, Spanish, and Portuguese tongues. 1879

The early history of the Mediterranean populations, &c., in their migrations and settlements : illustrated from Autonomous Coins, Gems, Inscriptions, &C. 1882

Examination of the Legend of Atlantis in Reference to Protohistoric Communication with America, London, 1886

Clarke,Hyde. The Century Cyclopedia of Names: A Pronouncing and Etymological Dictionary of Names in Geography, Biography, Mythology, History, Ethnology, Art, Archæology, Fiction, Etc. New York: Century Co, 1904.